The present invention relates generally to the field of RAID (redundant array of independent storage devices) storage, and more particularly to RAID protection levels.
The Wikipedia entry for “RAID” (http://en.wikipedia.org/wiki/RAID as of 18 May 2015) states as follows: “RAID (originally redundant array of inexpensive disks; now commonly redundant array of independent disks) is a data storage virtualization technology that combines multiple disk drive components into a single logical unit for the purposes of data redundancy or performance improvement . . . . Data is distributed across the drives in one of several ways, referred to as RAID levels, depending on the specific level of redundancy and performance required. The different schemes or architectures are named by the word RAID followed by a number (e.g. RAID 0, RAID 1). Each scheme provides a different balance between the key goals: reliability, availability, performance, and capacity. RAID levels greater than RAID 0 provide protection against unrecoverable (sector) read errors, as well as whole disk failure.”
In conventional RAID systems: (i) the files stored on the RAID system at different “protection levels”; and (ii) the protection level at which a given file is stored in the RAID system not defined on a single file level (that is a stored-file-by-stored-file basis) but, rather, on lower pool level. Protection level relates to the availability properties defined by Raid levels 0.1.2.3.5.6.10 . . . .